KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 176 insertions, 0 deletions

diff --git a/arch/mips/boot/Makefile b/arch/mips/boot/Makefile
new file mode 100644
index 000000000..8473c4671
--- /dev/null
+++ b/arch/mips/boot/Makefile
@@ -0,0 +1,176 @@
+#
+# This file is subject to the terms and conditions of the GNU General Public
+# License.  See the file "COPYING" in the main directory of this archive
+# for more details.
+#
+# Copyright (C) 1995, 1998, 2001, 2002 by Ralf Baechle
+# Copyright (C) 2004  Maciej W. Rozycki
+#
+
+#
+# Some DECstations need all possible sections of an ECOFF executable
+#
+ifdef CONFIG_MACH_DECSTATION
+  e2eflag := -a
+endif
+
+#
+# Drop some uninteresting sections in the kernel.
+# This is only relevant for ELF kernels but doesn't hurt a.out
+#
+drop-sections := .reginfo .mdebug .comment .note .pdr .options .MIPS.options
+strip-flags   := $(addprefix --remove-section=,$(drop-sections))
+
+hostprogs := elf2ecoff
+
+suffix-y			:= bin
+suffix-$(CONFIG_KERNEL_BZIP2)	:= bz2
+suffix-$(CONFIG_KERNEL_GZIP)	:= gz
+suffix-$(CONFIG_KERNEL_LZMA)	:= lzma
+suffix-$(CONFIG_KERNEL_LZO)	:= lzo
+
+targets := vmlinux.ecoff
+quiet_cmd_ecoff = ECOFF	  $@
+      cmd_ecoff = $(obj)/elf2ecoff $(VMLINUX) $@ $(e2eflag)
+$(obj)/vmlinux.ecoff: $(obj)/elf2ecoff $(VMLINUX) FORCE
+	$(call if_changed,ecoff)
+
+targets += vmlinux.bin
+quiet_cmd_bin = OBJCOPY $@
+      cmd_bin = $(OBJCOPY) -O binary $(strip-flags) $(VMLINUX) $@
+$(obj)/vmlinux.bin: $(VMLINUX) FORCE
+	$(call if_changed,bin)
+
+targets += vmlinux.srec
+quiet_cmd_srec = OBJCOPY $@
+      cmd_srec = $(OBJCOPY) -S -O srec $(strip-flags) $(VMLINUX) $@
+$(obj)/vmlinux.srec: $(VMLINUX) FORCE
+	$(call if_changed,srec)
+
+UIMAGE_LOADADDR  = $(VMLINUX_LOAD_ADDRESS)
+UIMAGE_ENTRYADDR = $(VMLINUX_ENTRY_ADDRESS)
+
+#
+# Compressed vmlinux images
+#
+
+targets += vmlinux.bin.bz2
+targets += vmlinux.bin.gz
+targets += vmlinux.bin.lzma
+targets += vmlinux.bin.lzo
+
+$(obj)/vmlinux.bin.bz2: $(obj)/vmlinux.bin FORCE
+	$(call if_changed,bzip2)
+
+$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
+	$(call if_changed,gzip)
+
+$(obj)/vmlinux.bin.lzma: $(obj)/vmlinux.bin FORCE
+	$(call if_changed,lzma)
+
+$(obj)/vmlinux.bin.lzo: $(obj)/vmlinux.bin FORCE
+	$(call if_changed,lzo)
+
+#
+# Compressed u-boot images
+#
+
+targets += uImage
+targets += uImage.bin
+targets += uImage.bz2
+targets += uImage.gz
+targets += uImage.lzma
+targets += uImage.lzo
+
+$(obj)/uImage.bin: $(obj)/vmlinux.bin FORCE
+	$(call if_changed,uimage,none)
+
+$(obj)/uImage.bz2: $(obj)/vmlinux.bin.bz2 FORCE
+	$(call if_changed,uimage,bzip2)
+
+$(obj)/uImage.gz: $(obj)/vmlinux.bin.gz FORCE
+	$(call if_changed,uimage,gzip)
+
+$(obj)/uImage.lzma: $(obj)/vmlinux.bin.lzma FORCE
+	$(call if_changed,uimage,lzma)
+
+$(obj)/uImage.lzo: $(obj)/vmlinux.bin.lzo FORCE
+	$(call if_changed,uimage,lzo)
+
+$(obj)/uImage: $(obj)/uImage.$(suffix-y)
+	@ln -sf $(notdir $<) $@
+	@echo '  Image $@ is ready'
+
+#
+# Flattened Image Tree (.itb) images
+#
+
+ifeq ($(ADDR_BITS),32)
+itb_addr_cells = 1
+endif
+ifeq ($(ADDR_BITS),64)
+itb_addr_cells = 2
+endif
+
+targets += vmlinux.its.S
+
+quiet_cmd_its_cat = CAT     $@
+      cmd_its_cat = cat $(real-prereqs) >$@
+
+$(obj)/vmlinux.its.S: $(addprefix $(srctree)/arch/mips/$(PLATFORM)/,$(ITS_INPUTS)) FORCE
+	$(call if_changed,its_cat)
+
+targets += vmlinux.its
+targets += vmlinux.gz.its
+targets += vmlinux.bz2.its
+targets += vmlinux.lzma.its
+targets += vmlinux.lzo.its
+
+quiet_cmd_cpp_its_S = ITS     $@
+      cmd_cpp_its_S = $(CPP) -P -C -o $@ $< \
+		        -DKERNEL_NAME="\"Linux $(KERNELRELEASE)\"" \
+			-DVMLINUX_BINARY="\"$(3)\"" \
+			-DVMLINUX_COMPRESSION="\"$(2)\"" \
+			-DVMLINUX_LOAD_ADDRESS=$(VMLINUX_LOAD_ADDRESS) \
+			-DVMLINUX_ENTRY_ADDRESS=$(VMLINUX_ENTRY_ADDRESS) \
+			-DADDR_BITS=$(ADDR_BITS) \
+			-DADDR_CELLS=$(itb_addr_cells)
+
+$(obj)/vmlinux.its: $(obj)/vmlinux.its.S $(VMLINUX) FORCE
+	$(call if_changed,cpp_its_S,none,vmlinux.bin)
+
+$(obj)/vmlinux.gz.its: $(obj)/vmlinux.its.S $(VMLINUX) FORCE
+	$(call if_changed,cpp_its_S,gzip,vmlinux.bin.gz)
+
+$(obj)/vmlinux.bz2.its: $(obj)/vmlinux.its.S $(VMLINUX)  FORCE
+	$(call if_changed,cpp_its_S,bzip2,vmlinux.bin.bz2)
+
+$(obj)/vmlinux.lzma.its: $(obj)/vmlinux.its.S $(VMLINUX) FORCE
+	$(call if_changed,cpp_its_S,lzma,vmlinux.bin.lzma)
+
+$(obj)/vmlinux.lzo.its: $(obj)/vmlinux.its.S $(VMLINUX) FORCE
+	$(call if_changed,cpp_its_S,lzo,vmlinux.bin.lzo)
+
+targets += vmlinux.itb
+targets += vmlinux.gz.itb
+targets += vmlinux.bz2.itb
+targets += vmlinux.lzma.itb
+targets += vmlinux.lzo.itb
+
+quiet_cmd_itb-image = ITB     $@
+      cmd_itb-image = \
+		env PATH="$(objtree)/scripts/dtc:$(PATH)" \
+		$(BASH) $(MKIMAGE) \
+		-D "-I dts -O dtb -p 500 \
+			--include $(objtree)/arch/mips \
+			--warning no-unit_address_vs_reg" \
+		-f $(2) $@
+
+$(obj)/vmlinux.itb: $(obj)/vmlinux.its $(obj)/vmlinux.bin FORCE
+	$(call if_changed,itb-image,$<)
+
+$(obj)/vmlinux.%.itb: $(obj)/vmlinux.%.its $(obj)/vmlinux.bin.% FORCE
+	$(call if_changed,itb-image,$<)
+
+# for cleaning
+subdir- += compressed tools